Such DC-to-DC converters with several converter circuits, which are also called converter cells, are known from the prior art. In particular, multi-phase DC-to-DC converters that comprise several converter circuits are known, for example, from DE 11 2008 004 030 T5 and DE 10 2009 054 957 A1. DC-to-DC converters are used, for example, in motor vehicles, in order to couple different electric systems to each other.
If a fault occurs in one of the converter circuits in a DC-to-DC converter with several converter circuits and this causes a short-circuit current, then this can be detected by the controller of the DC-to-DC converter. After the detection of the short-circuit current, the controller switches off the defective converter circuit. From the moment when the short-circuit current occurs up to the moment when the defective converter circuit is switched off, in the known DC-to-DC converters, time can pass that is long enough to allow an increase of the current through the DC-to-DC converter. This current can be so high that the voltages are applied to the networks coupled via the DC-to-DC converters and the networks become unstable or one of these networks becomes unstable. Thus, the monitoring of the currents flowing through the converter circuits by means of the controller can be too slow to prevent a breakdown of the networks.
This is where the present invention comes into play.
The invention is based on the problem of quickly switching off a converter circuit of a DC-to-DC converter of the type named above in the event of a short circuit.